Study On Appraisal And Retrofit For Damaged P.C. Beams Subject To Fire Disaster

In recent years, building fire accidents occur frequently in China, which cause lots ofdirect economic loss as well as a large number of casualties and bring a static element to thestate and society. As we all know, the fire will cause various degrees of damage to thebuilding structure, it is obviously uneconomic for us to demolish and reconstruct the damagedhouse. Therefore, we should repair and strengthen the buildings which are not damagedseriously to improve their bearing capacity and durability and allow them to continue toservice and to make full use of their function.Firstly, according to the damaged building structure site after the fire in a chemical fiberfactory workshop, corresponding detection methods were used to identify the damagedcomponents and rate the extent of the damage. Then think over the effect of fire onmechanical property and thermal parameters of concrete and prestressed steel bars by usingthe finite element software Midas FEA do the numerical simulation and analysis ofprestressed concrete beams after fire damage. Contrast the changes in stress and strain ofprestressed beam before and after the fire and summarize the difference. Finally, according tothe numerical simulation, contrast several common engineering methods of reinforcement ofprestressed concrete beams, which proves that the method of strengthening the damagedprestressed concrete beams by bonding U-shaped steel is still good to be used and has a goodreinforcement effect.The prestressed beam of this article is variable cross-section roof beam and prestressedsteel bars are distributed like curve, which are uncommon in domestic articles. It caneffectively make up for the loss of prestressing by pasting U-shaped steel to strengthendamaged prestressed beams, which has an important significance to adopt this method toreinforce the similar projects.